Influence of nanostructure on shrinkage and recovery in ambient pressure dried methyltrimethoxysilane aerogels

Kurzfassung

In this work, we employ real-time video analysis to monitor dimensional changes during ambient pressure drying of MTMS-derived aerogels. By varying the water-to-precursor molar ratio, we fabricate gels with three distinct microstructures obtained through supercritical drying: nanoporous, co-continuous, and particle-aggregate, while maintaining the porosity and density. We then systematically wash the gels with solvents of differing polarity and protic character (protic, aprotic, polar, and non-polar) to assess how solvent properties influence capillary stress development during drying. The resulting shrinkage dynamics and recovery behavior are quantified and correlated with the solvents physicochemical properties. Finally, we compare the microstructural evolution of APD and supercritically dried samples using scanning electron microscopy (SEM), offering direct visualization of the morphological outcomes linked to drying method and solvent choice.